Writing instrument



March 26 1946. J. BIRO WRITING INSTRUMENT 2 Sheets-Sheet 2 Filed June17, 1945 1 J. .ELIO

a b Q Q s Patented Mar. 26, 1946 2,397,229 WRITING INSTRUMENT LaszloJozsef Biro, Buenos Aires, Argentina, as-

signor, by mesne assignments, to "Eterpen Sociedad Anonima Financiera,also known as Eterpen S. A., Buenos Aires, Argentina, a company ofArgentina Application June 17, 1943, Serial No. 491,208 In Argentina May19, 1943 25 Claims.

This invention relates to improvements in fountain pens of the ball-tiptype, and particularly to means for providing a regular ink feed to theball constituting the active or writing element thereof.

Many improvements have been made in fountain pens having a rotatablymounted small ball instead of the usual writing pen, but no satisfactoryimprovements have been made in the ink reservoir, to the extent thatmanufacturers are still using the simple charge reservoir requiringauxiliary elements such as valves and other means capable of aiding inthe feed of ink and avoiding undue oozing thereof.

From actual experiments it has been ascertained that the most suitableink for ball-tip fountain pens is the so-called dense ink, which is veryadhesive and in rotating the ball a thin film of ink will pass to theexterior thereof regularly and in a quantity suflicient to mark neat andnormal strokes.

While being dense, said ink is sufficiently liquid to pass through smallinterstices, and it is therefore a problem to confine the ink withouteliminating the corresponding air intake to enable the pen to work bygravity. Also, in the case of a barrel-shaped reservoir, the mass of inkwill tend to seek its level, changing its position as the instrument ismoved about, and this means that when raising the tip of thefountain-pen, there is a risk of losing the necessary contact betweenthe general ink mass and the feeder, due to the formation of bubbleswhich might interrupt the normal working of the instrument.

Therefore, it would be ideal to constitute an ink reservoir wherein thegravity would not alter the position of the liquid and wherein thecharge would be kept in perfect condition to provide a feed constitutedby a vein of liquid, and this is exactly what is attained by means ofthe improvements subject of the present invention.

The ink reservoir of the present invention is constituted by one or moreconduits arranged so as to acquire the nature of a coil concurrent tothe ball feeder and acting as a base therefor.

To this end, the conduit constituting the reservoir is preferably ofhelical or other similar shape or arrangement following an extended pathfrom a corresponding air-intake to said feeder.

It is an object of this invention to constitute a reservoir having alarge capacity and capable of holding the ink so as to form anuninterrupted liquid vein within said conduit.

A further object of the invention is to condition the ink so that itwill lose the properties of the liquid, 1. e., that it will maintain itscondition within the conduit regardless of any changes in the positionof the instrument.

A still further object of the invention is to provide a combinationwhich will counteract the influence of gravity when the instrument isplaced with the air-intake downwards, since due to the fact that theconduit forming the reservoir being of small cross-section, i. e., notmore than say 5 square milliameters in area will act as a pipette theupper portion of which is kept closed by the writing ball, theatmospheric pressure will be sufficient to prevent the ink from oozingout of said air-intake.

A further object of the invention is to provide air-intakes constitutedby a simple orifice, without requiring the use of check-valves or otherauxiliary means, inasmuch as the vein of liquid will act as a closedpipette and, therefore, can: not return to the air-intake even if thelatter is located downwardly due to the position of the instrument.

A further object is to avoid interruptions in the feed of theinstrument, since the vein of liquid established by the ink charge inthe reservoir will -be in' constant contact with the ball feeder.

A still further object is to provide an ink reservoir of simplestructure and which will be substantially strong, for which purpose theconduit may be obtained by means of channels in the shape ofscrew-threads, closed by contact with a body with which it is combinedin order to constitute the reservoir within the instrument barrel.

A still further object is to provide means for replacing the charge ofink through detachable reservoirs.

A still further object is to provide a simple writing instrument of thefountain-pen type which will not require auxiliary means for causing theink to reach the writing ball.

The above and. other objects and advantages of the present inventionwill become apparent from the course of the following description, whenread in conjunction with the accompanying drawings illustrating, by wayof example, some of the preferred embodiments of the invention, andwhere- Flg. 1 is a view of the writing instrument, partially in sectionso as to disclose the interior thereof and the wound reservoir which, inthis particular instance, is formed by a screw-like body having ahelical channel which is closed into a the internal section of the sothat whensaid body 1 is cylinder, the channels 5 ditions, said channels5' conduit upon introducing said body into the barrel of the writinginstrument.

Fig. 2 is a cross-sectional view line NN of Fig. 1.

Fig. 3 shows a further embodiment of the reservoir which, in thisparticular instance, -is formed by means of a helical channel obtainedby an internal screw-thread formed in the barrel, the conduit beingclosed on one side by means of a cylindrical body adapted as a malemember.

Fig. 4 shows an embodiment similar to that of Fig, 1, but wherein thescrew-thread is provided with two ormore admissions instead of one,which means that there are two or more helical conduits ending at theball feeder.

Fig. 5 is a longitudinal sectional view of the writing instrument in afurther embodiment, wherein the reservoir is constituted by a detachablebody within the fountain-pen barrel; and

Fig. 6 is a view graphically showing the separation of the reservoir as'a removable and rechangeable body. I

The same reference characters are used to indicate like or correspondingparts or elements throughout the drawings.

As may be seen from the drawings, a is the handle of the writinginstrument terminating in a tip b carrying the writing ball i. This ballis suitably mounted so as to provide a spherical.

portion projecting sumciently to engage the writing. surface. However,said ball is held by a setting 2 sufliciently closely fitted to form aclosure but free to rotate and hold a coating of ink which will pass outof the instrument upon rotating said ball for writing purposes.

In order to constitute the setting for said ball I, said tip b isprovided with a concave socket 3 V with which the ink feeding channel 4receiving the liquid from the reservoir communicates.

Said reservoir c-constituted by at least one conduit 5, which ispreferably helical and, as shown in the drawings, starts at theair-intake 6, extending to the feeder 4. g In the embodiment of Fig. 1,the reservoir 0 is formed by combining the body] and a cylinder 8constituted by the handle or barrel a. .For this purpose,-said body 1 isthreaded so as to provide a helical channel The cross-section of saidchannel 5' is relatively'small, for example of a section of less than 5mm}, and the maxi I will coincide with cavity of cylinder- 8 housedwithin said will remain closed by mum diameter of said body the walls ofsaid cylinder v will acquire the nature of a coil-like conduit capableof constituting the.

vein of liquid when charged with ink.

As stated hereinbefore, the embodiment shown and also form a helicalconduit 5, capable of establishing a liquid vein from the air-intake 6to the feeding channel 4. In this-embodiment of Fig. 3, the air-intake 6is protected by a cap taken along the 8. Under these con- Fig. 3comprises a helical conduit similar to I remain 40 ple replacement ofsaid body c constituting the 2, the ball I will 9 having a correspondingorifice- S'VCOITBSDOHCL. 1

. ing tosaid air-intake.

Fi 4 shows a further embodiment of the invention-similar to that of Fig.1 in that said instance, the threaded main closed so reservoir is alsoformed by a conduit comprising a cylinder 8 and body 1, except that inthis body 1 has two or more conjugate channels following the samehelical course, after the fashion of a screw with several threads. Thestarting point :of each channel will constitute an air-intake 6, and allthe screwthreads terminate at thefeeding channel 4, as shown. V

Inasmuch as each thread is constituted by a channel 5', and saidchannels are closed through" the combination of the body der 8, thismeans that there of helical conduits 5 starting at the air-intakes 6 andterminating at the feeding channel 4.

In the embodiment of Figs. 5 and 6,-the reservoir c is formed in a bodywhich is independent of the handle a and detachably housed within thecavity of said handle or barrel. In this instance, said reservoir 0 isformed by a body 0' having a cylinder In terminating in a nozzle l0,through which the tube .4 of feeder 4 is screwed. Within said cylinderI0, is

1 within the. cylinjusted against the walls ofsaid cylinder I 0, so asto also form a helical conduit 5 terminating at the feeder 4, so thatwhen charged with ink, it will form a liquid vein which will reach theball i in the same manner as in the previous embodiments.

Inasmuch as the handle or barrel a will serve as a casing for the body0, constituting the reservoir c, it will be suflicient to detach saidhandle as shownin Fig. 8, in order to remove the. body 0'. In order toremove said bodyc, tube a should be unscrewed, whereby said body 0' willfree for removal and replacing. Thus, if the ink in the fountain-pen hasbeen exhausted, the charge may be replaced through the simreservoir.

From the foregoing it may be seen that in any of the embodiments.illustrated in the difierent figures, the reservoir c acquires thecharacter of a conduit starting at the corresponding airintake 6 andending at the feed channel .4.

Incharging the reservoir c with dense ink, all the cavities of thesystem constituted by the channels should be filled, or in other words,the reserv voir 0 should contain a intake 6 to the ball I. I

Inasmuch as the conduit 5 of said reservoir 0 is of small section, i.e., having a cross-section of fullcharge, from the airnot more than say5 square millimeters, when charged with ink it will form anuninterrupted vein of liquid, as if it constituted an extension ofchannel 4. Due to the close fit of said ball I in the setting 2, the tipof the instrument will rethat the ink cannot discharge by gravity.

Notwithstanding the adjustment of the setting act as an intermediarymeans between.'the ink charge-and the writing surface. since due to theadhesive properties of the ink, upon rotating saidball it will be coatedtherewith, said coating 4 so as to defineperfectly regular strokes.

As the ink is consumed through use of the instrument, the charge in'theform of a liquid vein will move bodily to occupythe space of the portioncarried out by the ball. I

Said vein of liquid is uninterrupted, and therefore the continuitythereof will be maintained as the ink is used, since the displacementwill take place throughout the vein, and hence there will will be aplurality a' body I which, being threaded as in the embodiment of-Fig.1, is adpassing out of the instrument feeding channel 4, which is asomaebeno risk of interruptions, as the rear terminal thereof is in contactwith the atmosphere by means of said air-intake 6.

The vein of ink reaches the ball through the followed by conduitconstituting the reservoir 0, so that said feed will be permanent andthe instrument will at all times be ready for use.

Inasmuch as the reservoir c is formed by a coil of small section fullycharged with ink, the instrument'may be placed in any position and usedin any manner without the established liquid vein being affected bygravity.

It is obvious that in carrying the invention into practice, severalchanges in construction and detail will occur to those skilled in theart, without departing from the scope of the invention as clear- 'ly setforth in the appended claims.

I claim:

1. A fountain pen of the type having a freelyrotatable writing ballmounted in a seat, an ink reservoir formed by a conduit whichcommunicates at one end with said seat and which, after following atortuous path, leads to an air-intake .at the end of the conduit remotefrom said seat.

2. A fountain pen of the type having a freelyrotatable writing ballmounted in a seat, an ink reservoir formed by a coil-shapedconduit whichcommunicates at one end with said seat and which, after following atortuous path, leads to an air-intake at the end of the conduit remotefrom said seat.

3. A fountain pen of the type having a freely-- rotatable writing ballmounted in a seat, an ink reservoir formed by a substantiallyhelicallyshaped conduit which communicates at one end with said seat andwhich, after following a tortuous path approximately from one to theother end of the instrument, leads to an air-intake at the end of theconduit remote from said seat.

4. A fountain pen of the type having a freelyrotatable writing ballmounted in a seat, an ink reservoir formed by a plurality ofsubstantially helically-shaped conduits each of which communicates atone end with said seat and which, after following tortuous pathsapproximately from one to the other end of the instrument, lead to airintakes at the ends of the respective conduits remote from said seat.

5. A fountain pen of the type having a freelyrotatable writing ballmounted in a seat, an ink reservoir formed by a conduit including agroove substantially longer than the reservoir which conduitcommunicates at one end with said seat and which leads to an air-intakeat the end of the conduit remote from said seat.

6. A fountain pen of the type having a freelyrotatable ball mounted in aseat, an ink reservoir formed by a combination of an externally threadedbody snugly fitted within a cylinder so that the helical channel formedby the thread is closed by said cylinder forming a conduit-whichcommunicates at one end with said seat and which leads to an air-intakeat the end of the conduit remote from said seat.

rotatable writing ball mounted in a seat, an ink reservoir formed by aconduit which communicates at one end with said seat and, afterfollowing a tortuous path approximately from one to the other end of theinstrument, leads to an airintake at the end of the conduit remote fromsaid seat, said reservoir being formed in a body detachably fittedwithin the barrel of said fountain pen. v

9. A fountain pen of the type having a freelyrotatable writing ballmounted in' a seat, an ink reservoir formed by a conduit ofsubstantially constant section which communicates at one end with saidseat and, after following an extended path, leads into an air-intake atthe end of the conduit remote from said seat, said conduit and feedchannel when charged with ink forming an uninterrupted vein of inkextending to said ball 1 seat.

10. A fountain pen of the type having a freelyrotatable writing ballmounted in a seat, an ink reservoir formed by a conduit of smallcross-sectional area which communicates at one end with said seat and,after following a path substantially longer than the entire length ofthe instrument, leads to an air-intake at the end of. the conduit remotefrom said seat.

11. A fountain pen of the type having a freelyrotatable writing ballmounted in a. seat, an ink reservoir formed by a conduit of small cross-Sectional area which communicates at one end with said seat and, afterfollowing an extended path approximately from one to the other end ofthe instrument, leads to anair-intakeat the end of the conduit remotefrom said seat, said conduit and feed channel holding the entire inksupply. 4 I

12. A fountain pen of the type having a freelyrotatable writing ballmounted in a seat, an ink reservoir formed by a conduit of substantiallyconstant section which communicates at one end with said seat and leadsto an air-intake at the end of the conduit remote from said seat.

13. A fountain pen of the type having a freely- .rotatable writing ballmounted in a seat, an ink reservoir formed by a conduit of substantiallyconstant section of less than five square millimeters which communicatesat one end with said seat and which leads to an air-intake at the end ofthe conduit remote from said seat.

14. A fountain pen of the type having a freelyrotatable writing ballmounted in a seat, an ink reservoir formed by a conduit of substantiallyconstant section which communicates with a feed channel of smallercross-section than said conduit which communicates with the seat forsaid ball and leads to an air-intake at the. end of the conduit remotefrom said seat, said conduit and feed channel when charged with inkforming an uninterrupted vein of ink extending to said ball seat.

15. A fountain pen of the type having a freelyrotatable writing ballmounted in a seat, an ink reservoir formed by a conduit of smallcrosssectional area which extends approximately from one to the otherend of the instrument, and leads into a feed channel of smallercross-sectional area which communicates with the seat for said ball, theend of the conduit remote from said ball being provided with anair-intake, said conduit and feed channel holding the entire ink supply.

16. In a writing implement for use with a dense adhesive ink, a writingball, a socket in which the ball is rotatably mounted. a feed channelfeed channel opening in a writing implement of substantially uniformwith an air vent to admit 3 in the conduit. v g I 121. A reservoir forholding a substantial quan-' opening forwardly into the socket, and a.1'3561'7 voir comprising an ink-holding .conduit which is adapted tohold the major part of the charge of ink for the writing implement andis of such cross-sectional area relative to the flow characteristics ofthe ink as to prevent the ink from flowing freely under gravity alone ineither direction in the conduit irrespective of the position of thewriting implement, said conduit being connected at one of its ends withsaid feed channel and being provided at its other end with a vent.

17. In a writing implement, a writing ball, a

socket in which the forwardly into the socket,

and a reservoir comprising an ink-holding contity of ink for use inwriting implement of the type having a writing a socketand a feedchannel opening forwardly into the socket; said reservoir comprising aninkholdingconduit which is adapted to 'hold the major part of the chargeof ink for the writing implement in the form of a continuous vein,saidconduit being adapted to be connected at one of its ends with saidvided at its other end with a vent, and said conduit being of such 'tothe fiowcharacteristics ofthe-ink as to mainball is rotatably mounted, a

duit which is adapted to hold the entire supply of ink for the writingimplement in the form of a continuous vein-and is of suchcross-sectional area relative to the flow characteristics vof the ink asto maintain the continuity of the ink vein irrespective of the positionof the writing-implement, said conduit being connected at one of itsends with said feed channel at its other end with a vent.

18. A reservoir for holding in continuous vein form'a substantialquantity of thick ink for use and being provided in' a writing implement'of the type having a writing ball rotatably mounted in a socket and afeed channel opening forwardly into the socket; said reservoircomprising an ink holding conduit which isadapted to hold the major partof the charge of ink for the writing implement and is of suchcross-sectional area relative to the con: sistency of the ink as toprevent the ink from flowing freely under gravity alone in eitherdiifection in the conduit irrespective of the position of the reservoir,said conduit being adapted for con-' nection at one" of its ends andbeing provided at its other end with a vent.

19. A reservoir for holding in continuous vein form a substantialquantity of thick ink for use with said feed channel the type having awritvein irrespective of ends into said channel ing ball rotatablymounted in a socket and a feed channel opening forwardly into thesocket; said reservoir comprising an ink holding conduit which isadapted to hold the entire supply of ink sectional area relative totheflow characteristics for the writing implement and isof such crossofthe ink as to maintain the continuity of the ink vein irrespective ofthe position of the reservoir, said conduit being adapted for connectionatone of its ends with said feedchannel and beingpro'videdatits otherend with a vent. 20. An ink reservoir for its length and is adapted tohold the entire ink supply, said conduit being adapted for connection'atone end with said feed channel to feed\ink to the socket andbeingprovided atits other end airas the ink advances use ina writingimplement of the type having a writing ball 'rotatably mounted in asocket and having a feed channel the socket; said reservoir and, afterfollowing a path I to'an air intake at the rotatable writing reservoirformed by a plurality 'of conduits of tain the continuity of the inkvein irrespective of the position of the writing implement.

22. A reservoir for holdinga substantial quane tity of ink for use in awriting implement of the holding conduit which .follows a. tortuous pathand is adapted. to-hold the entire supply of-inkv for the writingimplement in the form of a con-' tinuous vein, said conduit beingadapted to be connected at one of its endswith said feed channel andbeing provided at its other end with a vent, and said conduit being ofsuch cross-sectional area relative to the fiow characteristics of theink as to maintain the continuity of the ink implement.

23. In a'writing implement, a writing tip for applying ink to thesurface being written upon,

is conducted to the tip, I closely arranged passages behind said'channelin which the main supply of ink for said tip is retained, said passagesall opening at their front ink in the passages in either direction underthe influence of gravity alone irrespective of the posi-- drawnat thetip. 4

24. A fountain pen of the type having a freelyrotatable writing ballmounted in a seat, an ink reservoir formed by a plurality of conduits ofsmall cross-sectional area, duits communicates at one substantiallylonger than the entire length of the instrument, leads end of theconduit remote from said seat. I

25. A fountain ballmounted in a seat, an ink small cross-sectional area,each of which conduits communicates at one end with said seat and,after'following a path approximately from oneend of-the instrument tothe other, leads to a respective air intake at ,the'end remotefrom saidseat, said plurality of conduits holding subentire ink supply. I

' 'LASZLO JOZSEF BIRD.-

ball rotatably mounted in feed channel and being procrosssectional' arearelativethe position' of the writing s and at their rear ends to 4 theatmosphere and being of such cross sectional area with respect to theflow characteristics of" the ink as to. prevent any appreciable flow ofthe each of which conend with said seatpen of the type having a freely

